Reduce Climate Change

Highway vehicles release about 1.7 billion tons of greenhouse gases (GHGs) into the atmosphere each year—mostly in the form of carbon dioxide (CO2)—contributing to global climate change. Each gallon of gasoline you burn creates 20 pounds of GHG. That's roughly 7 to 10 tons of GHG each year for a typical vehicle.
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How can a gallon of gasoline create 20 pounds of carbon dioxide?

It seems impossible that a 6.3-pound gallon of gasoline could produce 20 pounds of carbon dioxide (CO2) when burned. However, most of the weight of the CO2 comes from the oxygen in the air rather than the gasoline.

When gasoline burns, the carbon and hydrogen separate. The hydrogen combines with oxygen to form water (H2O), and carbon combines with oxygen to form carbon dioxide (CO2).

A carbon atom has a weight of 12, and each oxygen atom has a weight of 16, giving each single molecule of CO2 an atomic weight of 44 (12 from carbon and 32 from oxygen).

Therefore, to calculate the amount of CO2 produced from a gallon of gasoline, the weight of the carbon in the gasoline is multiplied by 44/12 or 3.7.

Since gasoline is about 87% carbon and 13% hydrogen by weight, the carbon in a gallon of gasoline weighs 5.5 pounds (6.3 lbs. x .87).

We can then multiply the weight of the carbon (5.5 pounds) by 3.7, which equals approximately 20 pounds of CO2!

We Can Help

Tailpipe CO2: the amount of CO2 emitted directly from the vehicle and a scale that shows emissions relative to other vehicles

Tailpipe & upstream GHG: greenhouse gas emissions (CO2, methane, and nitrous oxide) from the vehicle's tailpipe, as well as "upstream" GHG emissions related to the production and distribution of the fuel used to power the vehicle